By now most should realize that SolarWinds is a compromise on an almost unimaginable scale. It is a crisis. While there are "indicators of compromise" there are no indicators of all compromises. While the attackers have concentrated on gathering intelligence on only a small number of target sites, all SolarWinds customers must assume that they are compromised and that there may be multiple backdoors into their systems for which there are no ICUs. Only a small number of enterprises, perhaps none, have sufficient control over the content of their systems to be sure that they are resistant to such backdoors.
In https://us-cert.cisa.gov/ncas/alerts/aa20-352a DHS/CISA has suggested that some enterprises under some circumstances will have to "rebuild (from scratch) hosts monitored by the SolarWinds Orion monitoring software using trusted sources." In fact, we may have to rebuild all enterprise systems.
President Obama's chief of staff, Rahm Emanuel, famously said in 2008, “You never want a serious crisis to go to waste. I mean, it's an opportunity to do things that you think you could not do before.” It would be tragic, if after rebuilding our systems, we should come away as vulnerable as when we started.
We should take Rahm's "opportunity" to introduce "zero trust," indeed zero trust on steroids. One might well start with a Software Defined Network. One should include mutually suspicious processes, strong authentication at all levels, and "least privilege" access control.
Rebuilding systems in month's that took decades to evolve is a daunting task. I am reminded of what my father taught me when I was just starting out in IT almost sixty years ago. "Son," he said, "all hard problems in information technology have one and the same answer: one application at a time." We can do this. We should use the crisis to overcome the inertia that has kept us from doing what we all know we should have done a while ago. We know what to do: all we need is the leadership to do it.
Do not worry about the cost. Much of what we need to do, we can do with available resources. For example, we can implement "least privilege" with available tools. It only requires a change in intent. In any case, there is always enough money to do that which must be done.